Kidneys obtained at autopsy were studied by immunofluorescence in order to detect the presence of glomerular deposits in 129 patients who had presented with solid tumors, and in 55 patients without carcinoma utilized as controls. Deposits were observed in 22 of the neoplastic patients (17%), but only in 3 of the others (5.4%) (p less than 0.05). Among all solid tumors, glomerular deposits were most often observed in digestive carcinoma (p less than 0.02). These deposits were usually mesangial and they were never subepithelial. IgG and/or IgM and/or C3 deposits were demonstrated in 14 of 22 patients, IgA deposits were present in the 8 others (36%). Thus malignant neoplastic diseases should be taken into account as a possible etiologic factor in IgA nephropathy and they should be looked for in older patients with Berger's disease.